alan pettit Posted August 15, 2011 Share Posted August 15, 2011 i removed a seriously stiff spark plug yeaterday from an old engine. although once it started to turn the plug came out easily enough Ive now found that teh bore thread must be damaged as new plugs refuse to turn properly and teh threads on them are coming out stripped. Any ideas as to how to solve the problem ? its an 1147 cc head .thank you Link to comment Share on other sites More sharing options...
Richard B Posted August 15, 2011 Share Posted August 15, 2011 Try cutting some slots in an old sparkplug at 90 degrees to the thread and use it as a thread chaser.Alternatively either a re-threader (if they do one for spark plug threads) or a Helicoil! Link to comment Share on other sites More sharing options...
That Man Posted August 15, 2011 Share Posted August 15, 2011 It sounds like that old spark plug was already cross threaded, the best way to try and salvage the thread would be to run a tap through the hole (M14 x 1.25 iirc )Probably just best taking the head to your local friendly machine shop and asking them nicely. I've seen the result of a spark plug blowing out, makes a nice dent in the bonnet ! Link to comment Share on other sites More sharing options...
alan pettit Posted August 15, 2011 Author Share Posted August 15, 2011 have ordered a chaser tool today .thanks for the help .the bonnet has enough dents already ! Link to comment Share on other sites More sharing options...
piman Posted August 15, 2011 Share Posted August 15, 2011 Hello Alan, you could have saved your cash, once the thread is stripped, chasing it will do no use, as it can't restore the metal. AlecPS, I see my original reply seems to have disappeared, I would take the head to an engine reconditioner and ask them to helicoil it. It's the only satisfactory repair. Link to comment Share on other sites More sharing options...
TedTaylor Posted August 16, 2011 Share Posted August 16, 2011 piman wrote:Hello Alan, you could have saved your cash, once the thread is stripped, chasing it will do no use, as it can't restore the metal. AlecA spark plug thread chaser is always a useful tool to have around. The original problem could have been something as basic as a build up of carbon in the thread at the bottom of the hole which a quick run down with a thread chaser will clear out (the small amount of carbon that may drop into the bore should not be a problem but grease on the chaser will help prevent this if you are worried). Presumably the plug came out undamaged so I doubt it was cross threaded.Also a nice clean thread (plug/thread chasers tend not to really cut the metal like proper taps so do not make the thread 'loose') might have made it easier to start the new plug. I suspect the problem was a combination of mucky thread and difficulty in starting the plug which caused you to cross thread the first one (it happens). This has damaged the thread and is why the other plugs have come out damaged.With the danger of dropping metal filings into the bore if the thread is damaged (though as I said grease on the tap/thread chaser helps to prevent) I would remove the head and have a good look at what is going on as the thread is 'recut'. If it is obvious that the thread is seriously damaged after the thread is cleaned up the plug may be loose in the hole and is a candidate for helicoiling.Ted Link to comment Share on other sites More sharing options...
piman Posted August 16, 2011 Share Posted August 16, 2011 Hello Ted, the original post said "and teh threads on them are coming out stripped", which is why I said a chaser would not be of any use?Although I don't have a spark plug chaser, (nor needed one in decades) I regularly tap holes during a rebuild for ease of assembly.Alec Link to comment Share on other sites More sharing options...
Steve Cureton Posted August 16, 2011 Share Posted August 16, 2011 Many years ago I had a similar problem in a Honda motorbike and that turned out to be dirt of some sort in the threads. A bit of careful working of the plug in & out with 3-in-1 on the thread eventually sorted it with no ill effects. It's always worth trying as if it does ruin the thread then you haven't lost anything except a bit of time. Link to comment Share on other sites More sharing options...
alan pettit Posted August 18, 2011 Author Share Posted August 18, 2011 I sorted it last night. Bought a chaser on ebay for a fiver and dully screwed it in and out. Hey Presto problem gone and spark plug went in no bother! Another job off my list ! Id recommend the chaser .its a Clarke one for 14m and 18m plugs. Link to comment Share on other sites More sharing options...
piman Posted August 18, 2011 Share Posted August 18, 2011 Hello Alan, glad you got it fixed so easily, but you did say the thread was stripped?Alec Link to comment Share on other sites More sharing options...
tengah spitfire Posted August 20, 2011 Share Posted August 20, 2011 Why do what mechanics, not fitters, have been doing for deacades and make your own chasers when you can go out and spend money buying one. Link to comment Share on other sites More sharing options...
alan pettit Posted August 24, 2011 Author Share Posted August 24, 2011 2353 wrote:Why do what mechanics, not fitters, have been doing for deacades and make your own chasers when you can go out and spend money buying one.Sorry but I dont understand what your point is. I'm a home mechanic /fitter .Its not my profession, Triumphs and tinkering are my hobby ,fortunately I have a job that allows me the cash to splurge on a fivers worth of convienience... Link to comment Share on other sites More sharing options...
piman Posted August 24, 2011 Share Posted August 24, 2011 Hello T.S., "not fitters,"I'm intrigued by that, but guess that you don't really know what a fitter is? Don't have the idea a fitter is someone who fits parts, a fitter is some one who makes things fit, a big difference.A shortened story told to me when I was an apprentice in a Lancashire Power Station. Power station manager to a fitter at a breakdown, "No spares, tha art a fitter arn't tha, mek un."Alec Link to comment Share on other sites More sharing options...
Richard B Posted August 24, 2011 Share Posted August 24, 2011 Before the days of Mr Whitworth and standard threads a fitter would find/make a nut and bolt fit together. Quite a skilled job.http://www.census1891.com/occupations-f.htm Link to comment Share on other sites More sharing options...
thescrapman Posted August 24, 2011 Share Posted August 24, 2011 piman wrote: I was an apprentice in a Lancashire Power Station. Power station manager to a fitter at a breakdown, "No spares, tha art a fitter arn't tha, mek un."AlecAlecI guess you were at Heysham, can't think of any others.Anyway, I think the original post mentioning "Fitters" was attempting to distinguish between mechanics and people that just fit parts, which is all many garages now employ, especially main dealers. The computer says "fit part X" so they fit part X, when it doesn't work, they are lost.Whereas fitters to you and me means the guys that would make and fit parts. In your case all around the Power Station.I have visited Power Statiobns like West Burton and Cottam over the last couple of years, they still have large teams of fitters, trained professionals, who keep the place in one piece, and do all the maintenance. Mostly in house, from fantastic workshops, Still not managed to get on site at Sizewell B (or C) yet, they seem to operate a closed shop and don't allow outsiders in to look at their IT kit.CheersColin Link to comment Share on other sites More sharing options...
piman Posted August 25, 2011 Share Posted August 25, 2011 Hello Colin, No it was Hartshead, Stalybridge, and it was a long time ago. From memory I think it was 125Mw and with six sets. I served my time as an electrical fitter, not a very well known trade?Alec Link to comment Share on other sites More sharing options...
thescrapman Posted August 25, 2011 Share Posted August 25, 2011 I'm not sure if Hartshead is till therem, I will have to go in search of one of the charts at work that shows who generates what and where.The old-school power stations are fascinating places. West Burton is 2GW, and has about 500 people on site to keep it running.Not a great fan of the new gas-fired ones, nothinh to them. Sutton Bridge is 250MW I think, never seems to have more than 8 people on site, and that includes the receptionist and security guard.We have at leaast 1 proper power station worker on here, though he now spends his days on the web and his nights at work sleeping, so you can't really describe his as a "worker" any more.He is currently mourning the loss of the workshop which was pulled down a few months ago, whilst he was away on paternity leave.CheersColin Link to comment Share on other sites More sharing options...
piman Posted August 25, 2011 Share Posted August 25, 2011 Hello Colin, I know it shut down some years ago. Alec Link to comment Share on other sites More sharing options...
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